1. Field of the Invention
The invention relates to a method for measuring the thickness of an opaque layer that constitutes an opaque laminated body in which a plurality of the opaque layers are laminated.
2. Description of Related Art
Grasping of the thickness of a layer that constitutes a multilayer body in which a plurality of the layers are stacked has been required. In this regard, a method for measuring the thickness of an opaque layer (opaque film) that constitutes the multilayer body is disclosed in, for example, Japanese Patent Application Publication No. 2001-194117 (JP 2001-194117 A). Specifically, etching is performed on the opaque film and a concave portion that penetrates the opaque film in a thickness direction is formed first during the measurement of the thickness of the opaque film regarding the multilayer body in which a wafer, a release layer, an insulating layer, and the opaque layer (opaque film) are stacked in this order. Then, transparent layers (transparent films) are formed in the concave portion and on the opaque film. Subsequently, the transparent layer formed on the opaque layer is removed, and then only the concave portion is in a state of being filled with the transparent layer. Then, light is applied to the transparent layer with which the concave portion is filled, and the thickness of the opaque layer that is adjacent to the transparent layer is measured based on the reflected light from the transparent layer.
According to the above-described measurement method disclosed in JP 2001-194117 A, however, the concave portion that penetrates the opaque layer needs to be formed and the transparent layer needs to be formed in the concave portion for the opaque layer thickness measurement, and much time is taken for the opaque layer thickness measurement. Accordingly, there has been a demand for a method by which the thickness of the opaque layer can be measured within a short period of time with regard to an opaque laminated body in which a plurality of the opaque layers are stacked.